This invention relates generally to apparatus for data transfer with a rotating data storage disk such as a flexible magnetic disk of three and a half inch diameter packaged in cassette form. More specifically, the invention pertains, in such rotating disk data storage apparatus, to an improved electrical connection of transducer leads to a flexible printed circuit board or equivalent conductor means.
The three and a half inch flexible magnetic disk and a disk drive for use therewith are both described and claimed in U.S. Pat. No. 4,445,157 to Takahashi. The magnetic disk is rotatably housed in a generally flat, boxlike envelope of relatively rigid plastic material, complete with a metal made sliding shutter, to make up a disk cassette. The envelope has a pair of apertures of rectangular shape to expose radial portions of the opposite sides of the magnetic disk. The sliding shutter also has a pair of apertures of approximately the same shape and size as the envelope apertures, which shutter apertures come into and out of register with the envelope apertures. The magnetic disk has a rigid hub of magnetic sheet metal attached centrally thereto. The hub has defined therein a central opening of square shape and an eccentric opening of rectangular shape.
When positioned in the associated disk drive, the magnetic disk has its central hub placed on a turntable which is much less in diameter than the disk. The turntable has a permanent magnet mounted thereon for attracting the disk hub. Disposed centrally on the turntable, a spindle engages in the central opening in the disk hub for centering the disk on turntable. A drive pin is disposed eccentrically on the turntable for driving engagement in the eccentric opening or slot in the disk hub, imparting the rotation of the turntable to the magnetic disk.
The disk drive for use with the three and a half inch disk has a pair of data transducers or read/write heads for data transfer with the opposite sides of the disk through the registered apertures in the envelope and the shutter. As disclosed in U.S. Pat. No. 4,811,140 to Enami et al., assigned to the assignee of the instant application, one of the transducers is mounted via a planar flexure seat on a carriage movable radially of the disk. The other transducer is mounted via another planar flexure seat on a load arm which is hingedly mounted on the carriage for pivotal motion toward and away from the disk.
Usually, with this type of disk drive, the leads of each transducer were soldered to a conductive pattern on a flexible printed circuit board disposed on that side of the associated flexure seat opposite to the one on which the transducer was mounted. Each soldered connection rose to a height of 0.3 to 0.6 millimeter. Negligible as it might seem, the solder of such height represented a serious inconvenience in reducing the thickness of the disk drive to an absolute minimum, as is the current trend.
It might be contemplated to dispose the flexible printed circuit boards on the same side of the flexure seats as the transducers. This solution is unsatisfactory, however, because the circuit boards might then contact the envelope of the disk cassette. Particularly in the case where the envelope has the metal made sliding shutter, the conductive patterns on the circuit board might be short circuited to the destruction of the transducers.